Steps needs to perform on Old Server:

2) Add a new network storage volume to take backup and mount it on folder "/NewBackup", make sure 'zimbra' user must have ownership on the backup path.
The size of backup volume must be equal to the size of store+hsm volume.

[Run as ROOT]
mkdir /NewBackup
chown zimbra:zimbra /NewBackup/

3) Mount new network storage volume to "/NewBackup/"

4) Change backup path and disable RealTime Scanner and redolog generation then restart mailbox service to take effect.

5) Run SmartScan and wait to finish both RealTime Scaning and SmartScan.
These processes will take time to finish, and the total time depend on the size of data in store.

zxsuite backup doSmartScan

6) Once backup is done, stop the services and mount the backup volume to newly installed server.

Steps needs to perform on New Server:

Note: Once the destination server is in production, existing connections will no longer be valid. Active users will need to login into the new system with the existing password.
ZCO and Zimbra Desktop Client profiles will need to be recreated. IMAP, POP and active-sync accounts will reload existing data.

1) Install new server with ZCS v8.8.12. [Do not create any new account]

2) Start SmartScan [it will be done within a minute]

su - zimbra
zxsuite backup doSmartScan

3) Now mount network storage volume from old server to path /NewBackupData/.
Ensure that the ‘zimbra’ user must have r/w permission on it.

5) If you are migrating a very large infrastructure where an export/import lasts for hours or even days, there is an alternative way to handle the migration from this point forward.
Instead of importing all of your data to the destination server, you can run a '"Provisioning Only"' import that will only create Domains, COSes and Accounts on the destination server, skipping all mailbox contents.

After doing this, switch the mailflow to the new server and, when the switch is completed, start the "real" data import.

zxsuite backup doExternalRestore /NewBackupData/

This way, your users will now connect to the new server where new emails will be delivered while old emails are being restored.

This approach has it's pros and cons, namely:

Pros:

Since items are only imported once and never modified or deleted afterwards, using this method will result in less discrepancies than the "standard" incremental migration.

This is the option that has less impact on the source server (e.g. good if you are in a hurry to decommission it).

Cons:

Depending on the timing of the operation, this method has a higher impact on your users due to the fact that items are restored WHILE they work on their mailbox.

Since the import is done on a running system, you might notice some slowdowns.

6) Post migration checks:

Run the following command to check and fix if there is any shares inconsistencies.
Second command will parse the import mapfile used as the first argument and fix any broken share. Mapfiles can be found in the Backup Path of the destination server as "map_[source_serverID]".

zxsuite backup doCheckShares
zxsuite backup doFixShares

7) After restoring data using the External Restore, there is a very high chance for the cache-based de-duplication not to catch many duplicates.
To fix message duplication we need to run following commands.

Steps needs to perform on Old Server:

1) Add a new network storage volume to take backup and mount it on folder "/NewBackup", make sure 'zimbra' user must have ownership on the backup path.
The size of backup volume must be equal to the size of store.

5) If previously full backup was taken on the server then take incremental backup.

/opt/zimbra/bin/zmbackup -i

Note: This step is optional, we can copy all available redologs /opt/zimbra/redolog/ to a safe location.

6) Once backup will be done. Stop all ZCS services, unmount backup volume and then shutdown the old server.

Steps needs to perform on New Server:

1) Install same ZCS version as installed on old server. OS can be different but the ZCS version must be identical.
Also, make sure that you configure the same domain, hostname, passwords as on the old server.

2) Once installation is done, stop all ZCS services.

zmcontrol stop

3) Take a backup of /opt/zimbra/conf/localconfig.xml, as you need to copy all the passwords from localconfig.xml (from the Full backup) and replace it in /opt/zimbra/conf/localconfig.xml file. [If same passwords were not set during installation]

4) Mount network backup volume on new server at folder /NewBackupData mount point. Make sure 'zimbra' user must have ownership on the backup path.

2) Prepare a new server and install same ZCS version and same ZCS services as installed on old server.

Follow the directions in the ZCS single server installation guide to install ZCS. Make sure that you configure the same domain, hostname, passwords as on the old server. During ZCS install, the following settings must be changed to match the original server settings:

Zimbra LDAP Server - For Domain to create - identify the same default domain as on the original server.